US2471471A - Apparatus for simultaneously inductively heating a plurality of articles - Google Patents

Description

May 31, 1949. A. o. WOOD 2,471,471

APPARATUS FOR SIMULTANEOUSLY INDUCTIVELY HEATING A PLURALITY OF ARTICLES Filed March 9, 1945 2 Sheets-Sheet l INVENTOR May 31, 1949. 2,471,471

A. 0. W00 APPARATUS FOR SIMULTANEOUSLY INDUCTIVELY HEATING A PLURALITY OF ARTICLES 2 Sheets-She'et 2 Filed March 9, 1945 INVENTO Patented May 31, 1949 APPARATUS FOR,

SIMULTANEOUSLY IN DUQTEVELY HEATING A PLURALITY F ARTICLES Alden G. Wood, Farina, Ohio, assignor to The Ohio Crankshaft Company, Cleveland, Ohio, a corporation oi? Ohio Application March 9, 1945, Serial No. 581,854 7 Claims. (01. 219-13) The present invention relates as indicated to parallel multiple inductors and is concerned primarily with inductors having a plurality of workreceiving openings disposed to heat several articles equally and simultaneously. In Patent No. 2,271,916, issued February 3, i942, and owned by the assignee of the present application, an inductor is shown and described which is capable of such equal and simultaneous heating. When several relatively large articles are to be heated the inductor shown in the patent becomes long, is somewhat difficult to support and requires considerable space making it necesary to provide special means for its use. It is usually desirable to keep the work-receiving openings canal in size to simplify the manufacture of the inductor and arrange these openings in a compact form to improve convenience of use. The present invention is concerned chiefly with meeting these re-- quirements as to ease of manufacture, convenience of use, and equality of heating.

Accordingly, the chief object of t.-e present invention has been to provide a multiple hole inductor having substantially equal work-receiving openings. Another object has been to provide such inductor with openings co: pactly and symmetrically arranged. An add nal object has been to provide an inductor having conductors for supplying the inducing current so disposed as not to disturb heating at any of its several heating stations. A further object has been to provide means for substantially independently cooling the portion of the inductor at each heating A further object has been to provide means for moving several articles simultaneously into corresponding inductors.

Other objects will become apparent from the following description and from the accompanying drawings which illustrate one form of my improved apparatus.

In the drawings:

Fig. 1 is a plan View showing the general form of inductor and the means for moving the Work pieces into the inductor openings;

Fig. 2 is an elevation taken as indicated at ?.2 of Fig. 1 and showing the inductor only;

Fig. 3 is an elevation partly in section taken as indicated at 33 of Fig. 1;

Fig. 4 and 4A show the construction of the upper ends of the pins for supporting and locating the work pieces; and,

Figure 5 shows an inductor of modified con struction embodying the present invention.

In the form of the apparatus illustrated provision is made for heating four articles simultaneously, the articles being supported in inductors 15*, I and 33 with properly selected clearances. Current of correct frequency is supby a suitable source Hi to terminals l5 and it. current, if assumed to enter through terminal iii passes in parallel through inductor members i7 and it which may be individual members as shown or combined into one member. current through member ll passes circumierentially around inductor loop l0 and that through member 18 passes around loop II. It then passes through members 20 and 2| respectively in parallel and then passes circumferentially around inductor loops l2 and I3 returning to the source M through inductor member 24- and ZElLE' QdE. 5. When loops ID and I2 have the same sectional areas and encircle articles identical with the articles encircled by loops H and it current in all of the four loops is the same and heating in all loops is equal.

To carry away the inductor power loss and to thus maintain maximum conductivity with a min mum amount of copper and to thus insure operation, an abundance of cooling water is supplied individually to each inductor loop to insure inductor temperature. Water i or loops l8 and ii is supplied through passages 26 and 2'! re pectively in terminal 15 and that for loops H. J. is is supplied by passages 29 and 38 through to inal it and member 2d. Each loop has its individual Water outlet. Fittings 32 and 33 serve as outlet passages for water from loops l0 and I 1 respectively and fittings 35 and 3'3 serve as corresponding outlet passages for loops [2 and I3.

3 illustrates the apparatus for elevating into the inductor loops, the parts, such as bearing races 35, which are to be heat treated. This elevating apparatus is carried on the floor of push ding tank. which in turn is supported by a suitable means. This apparatus comprises a vertically moveable platform 40 having four groups of three pins each such as 4|, each group of pins corresponding in location with each inductor loop. The three pins of each group are disposed triangularly, each pin of each group bein a vertex of a generally equilateral triangle. The upper end of each pin is machined to provide a supporting ledge having an ledge 45 to engage a lower side of a bearing race and hold the race at correct elevation and to provide a vertical face with an edge 46 to engage an inner peripheral surface of the bearing race to center the race in the corresponding inductor loop. These pins are of relatively small diameter to reduce to a minimum the heat generated in them when the races are being heated.

Platform 40 which carries pins ll supporting the race to be hardened is attached to plate 50 which is carried by elevator i and spaced therefrom by members 52 and 53, through bracket 55. The elevator is supported by piston rod 56. This piston rod is actuated by a piston in cylinder 58. To insure that the elevator moves in a straight line, guide rods Eli and 6! are provided which pass through suitable clearance holes in bracket 55 and one of them passes through lower support 62 which is also attached to the elevator.

Fluid to operate the piston is supplied to cylinder 58 by means of suitable piping. Fluid supplied by piping 63 raises the elevator by forcing the piston upwardly and fluid from piping 64 .forces it down providing rapid and positive movement of the elevator in both directions. A fourway valve 65 controls the supply of fluid and is usually operated by a timer-controlled solenoid 65.

In operation the bearing races or other articles to be heat treated are manually placed on pins 4| and power is applied for an interval of time usually regulated by a timer, to heat the race. The timer then interrupts the power supply and by its supply of current to solenoid 66 operates valve 65 to rapidly lower elevator and plunge the races into a quenching medium in tank 35. After a predetermined quenching interval platform 4i] is again raised by further timed operation of valve 65 and the races are removed and replaced by other races to be heat treated.

Numerous modifications may be made in the details of the apparatus such, for instance, as combining conductors H and it into one conductor with a single water passage therethrough. The inductor loops may be attached directly to the conductors. such as loop Ill being joined to conductors il and Zil with members Hi and H greatly reduced or eliminated and the width of space 12 therebetween may be varied. The in ductor loops may be of any desired form to accommodate the part to be heated, but are always disposed to bridge the space between members such as l and H or between adjacent ends of conductors such as H and 20. The number of inductor loops may be increased or decreased as desired and these may be variously arranged along the connecting conductors. Thus, in Figure 5, there is shown an inductor having a total of six inductor loops I8 arranged in groups of three in series and the groups of three being connected in parallel. Further, it is not necessary that the loops be disposed oppositely as shown, but may be arranged in staggered formation along the supply conductors.

Other forms may be employed embodying the features of my invention instead of the one herein explained, change being made as regards the means and the steps herein disclosed, provided the elements or steps stated by any of the following claims or the equivalent of such stated elements or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In apparatus of the class described, a multiple inductor comprising a pair of substantially parallel conductors defining a plane, each conductor comprising an inductor loop in series therewith, axes of the loops being in generally parallel spaced positions and perpendicular to the plane of the conductors, the loops being on generally opposite sides of the pair of conductors and being disposed to substantially encircle metallic articles lying in generally parallel positions, the pair of conductors having a common return circuit conductor lying generally parallel to the said pair of conductors but remote from the articles to be heated, and means for supplying inducing current to the pair of conductors to flow in parallel therethrough to heat simultaneously two of the said articles being encircled by the aforesaid loops.

2. In apparatus of the class described for simultaneously and equally heating a plurality of metallic articles, an inductor comprising two generally parallel conductors, each conductor comprising an inductor coil bridging a cut in said conductor and being adapted to be electrically coupled to an article to be heated, the parallel conductors having a common return circuit conductor lying in generally close parallel relation with generally straight portions of said parallel conductors and remote from the coils.

3. In apparatus of the class described for heating surface zones of a plurality of articles in a limited space, a pair of generally parallel and closely spaced supply conductors, each supply conductor comprising a plurality of inductor coils adapted to serve as inductors to heat the articles when the articles are in the coils, the coils being disposed generally on opposite sides of the pair of parallel conductors and lying substantially in the plane of said conductors, means for flowing current in parallel through the supply conductors, the inductor coils of each conductor being in series, and a return conductor lying in closely spaced parallel relation with the supply conductors and remote from the coils to neutralize inductive heating by current in the parallel parts of the supply conductors substantially without affecting heating in the coils.

4. In apparatus for simultaneously heating a plurality of metallic articles a circuit comprising three closely spaced generally parallel conductors extending generally away from and being con-v nected to a source of inducing current, two of said conductors comprising a delivery branch and the other conductor being a return branch of the circuit, each conductor of the delivery branch having a plurality of openings, and current conducte ing coils bridging the openings and extending generally laterally from the conductors, the said coils serving as inductors for heating the aforesaid articles and lying substantially out of magnetic fields of the parallel conductors.

5. In an inductor for simultaneously heating a plurality of metallic articles, two pairs of inductor coils, each coil being disposed generally in a corner of a square, conductors connecting the coils of each pair in series, a, supply conductor and a return circuit conductor connecting the pairs of series coils parallel and to a common source of inducing current, said return circuit conductor lying in close parallel relation with the conductors connecting the coils.

6. In an inductor for simultaneously heating a plurality of metallic articles, a plurality of inductor coils, said coils being arranged in a plurality of groups, conductors connecting the coils of each group in a series electrical relationship, the groups being arranged in parallel electrical relationship, a supply conductor and a return-circuit conductor connecting the parallel connections of the groups to a common source of inducing current, said return-circuit conductor lying in close parallel relationship with the con; 7

ductors connecting the coils of each group in semes.

7. In apparatus for simultaneously heating a plurality of metallic articles, a, circuit comprising at least a pair of closely-spaced, generally-parallel conductors extending generally away from and being connected to a source of inducing current, at least one of said conductors comprising a delivery branch and at least one of the other conductors comprising a return branch of the circuit, said delivery-branch conductor having a plurality of openings and current-conducting coils bridging the openings and extending generally away from said conductors, the said coils serving as inductors for heating the aforesaid articles and lying substantially out of magnetic fields of the parallel conductors.

ALDEN O. WOOD.

6 REFERENCES CITED The following references are of file of this patent:

UNITED STATES PATENTS record in the OTHER REFERENCES American Machinist, March 16, 1944, vol. 88, No. 6, pages 91-93.

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